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Ocular hemodynamic changes and flow direction of the ophthalmic artery and its relationship with degree of stenosis in patients with severe internal carotid stenosis

Objective To observe the ocular hemodynamic changes and flow direction of ophthalmic artery of patients with severe internal carotid stenosis (ICAS) and investigate the relationship between flow direction of ophthalmic artery and degree of stenosis. Methods Forty eyes of 40 patients with unilateral highgrade ICAS (29 eyes, 72.5%) and internal carotid artery occlusion (11 eyes, 27.5%) diagnosed by color Doppler flow imaging (CDFI) were enrolled in this study. There were 14 eyes (35.0%) with obvious ocular signs of ischemia, 26 eyes (65.0%) without obvious signs of ocular ischemia. The peak systolic velocity (PSV) of central retinal artery (CRA) was measured. The flow direction of the ophthalmic artery was observed by digital subtraction angiography (DSA). The PSV of CRA in eyes with different flow directions in the ophthalmic artery was comparatively analyzed. The relationship between flow direction of the ophthalmic artery and degree of stenosis was also analyzed. Results The PSV of CRA in ICAS eyes was (6.59plusmn;1.49) cm/s, which was decreased compared to fellow eye (8.95plusmn;1.35) cm/s, the difference was statistically significant (t=-7.24,P＜0.01). The PSV of CRA in eyes with signs of obvious ocular ischemia was (5.84plusmn;1.42) cm/s, which was decreased compared to eyes without signs of obvious ocular ischemia (7.00plusmn;1.39) cm/s, the difference was statistically significant (t=-2.49,P＜0.05). There were 15 eyes (37.5%) with retrograde flow in the ophthalmic artery, 25 eyes (62.5%) with forward flow of ophthalmic artery. The PSV of CRA in eyes with retrograde flow and forward flow of ophthalmic artery were (6.96plusmn;2.09), (7.01plusmn;1.42) cm/s, the difference was not statistically significant (t=-0.09，P＞0.05). Among 15 eyes with retrograde flow of ophthalmic artery, there were five eyes (33.3%) with unilateral high-grade ICAS, 10 eyes (66.7%) with internal carotid artery occlusion. The incidence rate of retrograde flow in the ophthalmic artery in eyes with internal carotid artery occlusion was higher than that in eyes with unilateral high-grade ICAS (P＜0.01). Conclusions The PSV of CRA in eyes with severe ICAS decreased compared to fellow eyes. The PSV of CRA in eyes with signs of obvious ocular ischemia also decreased compared to eyes without obvious signs of ocular ischemia. With the increase of the degree of the internal carotid artery stenosis, the incidence of retrograde flow of ophthalmic artery increased.